Apparatus and methods of packaging and testing die

ABSTRACT

Apparatus and methods of packaging and testing die. In one embodiment, a stacked die package includes a packaging substrate having a first surface with a recess disposed therein and a plurality of conductive leads coupled thereto, a first die attached to the packaging substrate within the recess and having a plurality of first bond pads electrically coupled to at least some of the conductive leads, and a second die attached to the first die and having a plurality of second bond pads that are electrically coupled to at least some of the conductive leads. When the stacked die package is engaged with, for example, a circuit board, the first surface of the packaging substrate is proximate the circuit board so that the packaging substrate at least partially encloses and protects the first and second die. The properties and dimensions of the packaging substrate are tailored to optimize the operational environment of the die, including improving thermal dissipation and enhancing performance of the die. In an alternate embodiment, the packaging substrate comprises an electrically conductive substrate and an electrically insulative material is formed between the conductive leads and the packaging substrate. In another embodiment, the first bond pads are electrically coupled to the conductive leads by wire-bonding. Alternately, the first bond pads are in direct contact with the conductive leads in a flip chip arrangement. In another embodiment, the die is sealed within an encapsulating layer to protect the first and second die.

TECHNICAL FIELD

[0001] The present invention relates to apparatus and methods ofpackaging and testing die for use in, for example, chip scale packagesand other similar devices.

BACKGROUND OF THE INVENTION

[0002] Conventional packaging of die in microelectronic devices involvestwo levels of packaging. FIG. 1 shows a first level of packaging of adie package 40 in accordance with the prior art. In this example, a die(or integrated circuit) 20 is attached to a lead frame 22 having aplurality of conductive leads 24 formed thereon. The die 20 is typicallyattached with a layer of adhesive epoxy or glue. Bonding pads 26 on thedie 20 are connected by bonding wires 28 to respective contact pads 30on the lead frame 22, a technique commonly known as wire-bonding. Thecontact pads 30 are electrically coupled to an inner end of eachconductive lead 24. In this representative example, each conductive lead24 has an outer end that terminates in a connecting pin 32. The die 20and lead frame 22 are then encapsulated by a cover 34, thus constitutingthe first level of packaging. In a second level of packaging, theencapsulated die and lead frame may be mounted to an electronics device,such as by inserting the connecting pins 32 into associated sockets on aprinted circuit board and securing the pins in place using solder reflowtechniques.

[0003] Recently, die have been mounted directly to a substrate, such asa printed circuit board, thus eliminating the lead frame and the firstlevel of packaging. Mounting of the die 20 directly to a circuit boardis generally referred to as chip-on-board (COB) packaging. For example,FIG. 2 shows the die 20 mounted directly to a circuit board 40 in a COBor “flip chip” packaging arrangement. In this arrangement, the bondingpads 26 are located on a bottom surface of the die 20. The circuit board40 has a set of terminals or conductive bumps 42 on one surface. Asshown in FIG. 2, the die 20 is mounted with the bonding pads 26 of thedie 20 facing the surface of the printed circuit board 40 to which thedie 20 is being mounted such that the bonding pads 26 make directcontact with the terminals 42. Thus, the bonding wires 28 and lead frame22 are eliminated.

[0004] It is customary to provide a layer of material known as a globtop or encapsulating layer 44 over the die 20 to hermetically seal thedie 20. The glob top 44 serves as a chemical insulator protecting thedie 20 from humidity, oxidation, and other harmful elements. The globtop 44 also protects the die 20 mechanically and relieves mechanicalstress in the die 20.

[0005] It is also known to stack die on top of another die to save spaceon the printed circuit board. For example, FIG. 3 shows a packagingarrangement having an inner die 50 mounted in a flip chip arrangement onthe circuit board 40 such that the bonding pads 26 of the inner die 50are in direct contact with the conductive terminals 42 on the circuitboard 40. An outer die 52 is attached to the inner die 50. Bonding wires28 extend from a set of second bonding pads 54 on the outer die 52 to aset of second terminals 56 on the circuit board 40. A glob top 44 isthen applied over the stacked die to hermetically seal and protect thedie 50, 52.

[0006] A conventional method of testing the stacked die 50, 52arrangement is to test the package after it has been completelyassembled. Testing of the die prior to packaging is typically limited tospot-checking of a random sample of the die while the die are attachedto the wafer. FIG. 4 shows a conventional method 60 of assembling andtesting stacked die on a printed circuit board (PCB). In a first step62, the inner die 50 is attached to the PCB 40 with the contact pads 26of the inner die 50 in contact with the terminals 42. The outer die 52is then attached to the inner die 50 in a second step 64, and the globtop is applied to encapsulate the die in a third “sealing” step 65.

[0007] In a fourth “testing” step 66, input signals are systematicallyapplied to the package to test all or some aspects of componentperformance, including speed, functionality, open circuits, shorts, andbum-in testing. In a fifth “determination” step 68, it is determinedwhether the package has performed the tests successfully. If so, theassembly and test method is complete 70.

[0008] If the package has not performed the tests successfully, it isdetermined whether the package has previously been reworked 72. If thepackage has been previously reworked but continues to fail the tests,the entire package is discarded in a “rejection” step 74, including theinner die, the outer die, and in some cases even the PCB. If the packagehas not been previously reworked, however, the package is reworked 76,and the package is returned to the testing step 66 for evaluation.

[0009] Although successful results have been achieved using theabove-referenced die packages, and methods of assembling and testingsuch die packages, certain disadvantages have been encountered. Forexample, because the glob top 44 is designed to protect the die fromenvironmental and mechanical stress, the materials used for the glob topare typically poor thermal conductors. Due to relatively poor heatdissipation through the glob top, the die or the PCB may become hotterthan desirable, particularly for stacked die or high-power dieapplications.

[0010] Furthermore, because the conventional method of testing the diepackage involves testing after the inner die has been attached to thePCB and the outer die has been attached to the inner die, if a packagedoes not pass a test successfully, the stacked die and PCB package mustundergo a time-consuming and costly rework procedure, or must bediscarded entirely. This is particularly true if the testing isperformed after the glob top has been applied.

SUMMARY OF THE INVENTION

[0011] The present invention is directed to apparatus and methods ofpackaging and testing die for use in, for example, chip scale packagesand other similar devices. In one aspect of the invention, a stacked diepackage comprises a packaging substrate including a first surface havinga recess disposed therein and a plurality of conductive leads coupledthereto, a first die attached to the packaging substrate within therecess and having a plurality of first bond pads, and a second dieattached to the first die and having a plurality of second bond pads,the first and second bond pads being electrically coupled to at leastsome of the conductive leads. When the stacked die package is engagedwith, for example, a circuit board, the first surface of the packagingsubstrate is proximate the circuit board so that the packaging substrateat least partially encloses and protects the first and second die. Theproperties and dimensions of the packaging substrate are tailored tooptimize the operational environment of the die, including improvingthermal dissipation and enhancing performance of the die. In analternate aspect, the packaging substrate comprises anelectrically-conductive substrate and an electrically insulative layeris formed between the conductive leads and the packaging substrate.

[0012] In another aspect of the invention, the first bond pads areelectrically coupled to the conductive leads by wire-bonding.Alternately, the first bond pads are in direct contact with theconductive leads in a flip chip arrangement. In another aspect, thefirst and second die are sealed within an encapsulating layer forprotection.

[0013] A method of packaging and testing a die package in accordancewith the invention includes testing a die having a plurality of bondpads formed thereon, determining that the die has tested successfully,providing a packaging substrate including a first surface having arecess formed therein and a plurality of conductive leads formedthereon, attaching the die to the packaging substrate within the recessand with the bond pads electrically coupled to at least some of theconductive leads to form the die package, and testing the die package.By integrating the testing and packaging of the die package, overallefficiency and yield is improved.

[0014] In another aspect of the invention, a method of packaging andtesting includes determining that the die package has not previouslybeen reworked. Alternately, a method includes reworking the die package.In another alternate aspect, a method includes determining that the diepackage is salvageable. If so, the die package may be salvaged.Alternately, a method includes sealing the die in an encapsulatinglayer.

[0015] An embodiment of a method of packaging and testing a stacked diepackage in accordance with the invention includes testing a first diehaving a plurality of first bond pads formed thereon, determining thatthe first die has tested successfully, testing a second die having aplurality of second bond pads formed thereon, determining that thesecond die has tested successfully, attaching the second die to thefirst die, providing a packaging substrate including a first surfacehaving a recess formed therein and a plurality of conductive leadsformed thereon, attaching the first die to the packaging substratewithin the recess and with the first and second bond pads electricallycoupled to at least some of the conductive leads to form the stacked diepackage, and testing the stacked die package.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is an isometric partially exploded view of a die and a leadframe package in accordance with the prior art.

[0017]FIG. 2 is a side cross-sectional view of a chip on board packagein accordance with the prior art.

[0018]FIG. 3 is a side cross-sectional view of a stacked die package inaccordance with the prior art.

[0019]FIG. 4 is a flowchart representation of a method of packaging andtesting of a stacked die package in accordance with the prior art.

[0020]FIG. 5 is a side cross-sectional view of a die package inaccordance with an embodiment of the invention.

[0021]FIG. 6 is a flowchart representation of a method of packaging andtesting of the die package of FIG. 5 in accordance with an embodiment ofthe invention.

[0022]FIG. 7 is a side cross-sectional view of a stacked die package inaccordance with an alternate embodiment of the invention.

[0023]FIG. 8 is a flowchart representation of a method of packaging andtesting of the stacked die package of FIG. 7 in accordance with anembodiment of the invention.

[0024]FIG. 9 is a side cross-sectional view of a stacked die package inaccordance with another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0025] The following description is generally directed toward apparatusand methods of packaging and testing die for use in, for example, chipscale packages and other similar devices. Many specific details ofcertain embodiments of the invention are set forth in the followingdescription and in FIGS. 5-9 to provide a thorough understanding of suchembodiments. One skilled in the art, however, will understand that thepresent invention may have additional embodiments, or that the presentinvention may be practiced without several of the details described inthe following description.

[0026]FIG. 5 is a side cross-sectional view of a die package 100 inaccordance with an embodiment of the invention. In this embodiment, thedie package 100 includes a packaging substrate 102 with a lower surface104 having a recess 106 disposed therein. The packaging substrate 102 ofthe die package 100 may be any suitable material, including a thermallyconductive material, such as metal.

[0027] A die 108 having a set of bond pads 110 is disposed within therecess 106 and attached to the packaging substrate 102. The die 108 maybe attached using a layer of adhesive epoxy or tape, or may bethermally-bonded (e.g. eutectically bonded), or may be attached by anyother suitable attachment mechanism. A corresponding set of contact pads112 are attached to the packaging substrate 102. In this embodiment, thecontact pads 112 are located within the recess 106. A bond wire 114electrically couples each bond pad 110 to a corresponding contact pad112 using conventional wire-bonding methods.

[0028] One may note that the bond pads may be electrically coupled withthe contact pads in a variety of ways, such as by tape automated bonding(TAB), microbump bonding, or flip chip bonding. Furthermore, althoughnot shown in FIG. 5, the die 108 may be sealed within an encapsulatinglayer, such as the glob top 44 layer of the prior art die packages shownin FIGS. 2 and 3.

[0029] In the die package 100, a set of via 115 are formed in thesubstrate 102. Conductive leads 116 are formed within the via 115. Anelectrically insulative layer 117 may be formed about each conductivelead 116 between the lead and the walls of the via 115, electricallyinsulating the conductive lead 116 from the substrate 102. Eachconductive lead 116 has an inner end proximate to the recess 106 coupledto a contact pad 112. As used in this application, the inner ends of theconductive leads 116 being “proximate” the recess 106 includes thecondition where the conductive leads 116 are at least partially withinthe recess 106, as shown in FIG. 5.

[0030] Each conductive lead 116 also includes an outer end coupled to aball pad 117 upon which may be formed a solder ball (or bump) 118. Thesolder balls 118 are then coupled with a corresponding set of terminals122 of an electrical circuit (e.g. a printed circuit board 120) by anyconventional method, such as, for example, by solder reflow techniques.Alternately, some other type of coupling device may be used instead ofsolder balls. For example, the solder balls 118 may be replaced withconnecting pins (FIG. 1) that engage receptacles on the printed circuitboard 120.

[0031] Throughout the following discussion, die packages are describedas being attached to the printed circuit board 120. It is understood,however, that the die packages may be coupled with any number ofsuitable devices, including test carriers, other electronic components,die packages, or electrical circuits. To simplify the followingdiscussion, however, the die packages will be described as beingattached to or engageable with a printed circuit board, allowing thereader to focus on the inventive aspects of the packaging and testing ofthe die.

[0032] One advantage of the die package 100 is that the packagingsubstrate 102 serves as both a lead frame and a protective cover for thedie 108. Two of the components of the conventional die package shown inFIG. 1 are therefore combined into a single element (i.e., the packagingsubstrate 102) with an associated reduction in the cost of packaging thedie.

[0033] Also, because the packaging substrate 102 may be a thermallyconductive material, improved cooling characteristics are achieved overprior art die packages. The dimensions and thermal properties of thesubstrate 102 may be tailored to the particular die 108, or theanticipated operational characteristics thereof, in order to optimizethe operational environment and extend the life of the die 108. Byproper adjustment of the mass, surface area, conductivity, reflectivity,etc. of the packaging substrate 102, for example, the dissipation ofheat away from the die 108 can be better regulated and controlled.particularly for high-power die applications. For a metallic or otherelectrically conductive packaging substrate 102, the electricallyinsulative layer 117 may be formed about the conductive leads 116 toelectrically insulate to prevent electrical shorts. If the packagingsubstrate 102 is not electrically conductive, the insulative layer 117may be eliminated, and the conductive leads 116 may be formed in the via115 in contact with the packaging substrate 102.

[0034]FIG. 6 shows a method of packaging and testing 600 of the diepackage 100 of FIG. 5 in accordance with an embodiment of the invention.As shown in FIG. 6, the die package 100 undergoes an integrated processof testing and packaging. In a first testing step 650, the die 108 maybe subjected to a battery of tests, such as speed, functionality,continuity, and bum-in tests. Next, it is determined whether the dietested successfully 652. If the die does not test successfully, it isdiscarded 654 and the process of packaging the die is ended 655.

[0035] If the die does test successfully, the die is attached to thepackaging substrate in an attachment step 656. After the attachmentstep, an abbreviated test 658 is performed on the die package,including, for example, continuity testing. It is then determinedwhether the die package tested successfully 660. If the die packagetests successfully, the process of packaging and testing of the die iscomplete 661.

[0036] If the die package does not test successfully, it is determinedwhether the die package have already been reworked 662. If not, the diepackage is reworked 664, and the die package is returned for testing658. If the die package has already been reworked, however, it isdetermined whether the die is salvageable 666. If the die issalvageable, it is salvaged by removing the die from the packagingsubstrate 668, and the die is returned to the step of attaching the dieto a packaging substrate 656. The old packaging substrate may bereattached and tested with a different die, or discarded. If the die isnot salvageable, the die package is discarded 670 and the process ofpackaging the die is ended 672.

[0037] The method of packaging and testing 600 of the die packageadvantageously improves the efficiency of the packaging and testing byintegrating testing steps into the packaging process. Because the die isinitially tested independently from the packaging substrate, if the diefails a test, the labor involved in packaging the bad die is saved.Also, diagnostic interpretation of the test results is simplifiedbecause the test failure can be immediately associated with the bad die.

[0038] Similarly, the method 600 improves the overall efficiency of thetesting of the die package. Since the die has been subjected to abattery of die-related tests (speed, functionality, etc.) the complexityof the testing of the die package is substantially reduced. Testfailures of the die package are therefore more easily and rapidlydiagnosed as being associated with the attachment of the die with thepackaging substrate. The amount of diagnostic work and die packagereworking is reduced, and overall, the testing process is more efficientthan the prior art method described above.

[0039]FIG. 7 is a side cross-sectional view of a stacked die package 200in accordance with an alternate embodiment of the invention. The stackeddie package 200 is similar to the previously described embodiment exceptthat a second (or outer) die 208 is attached to the first (or inner) die108 and partially disposed within the recess 106. As described above,the bond pads 110 of the first die 108 are connected by first bond wires114 to corresponding first contact pads 114 on the lower surface 104 ofthe substrate 102. In this embodiment, however, the first contact pads112 are not disposed within the recess 106, but rather, are proximatethe recess 106 on the lower surface 104 of the packaging substrate.

[0040] As shown in FIG. 7, the second die 208 has a set of contact pads210 that are electrically coupled by second bond wires 214 to a set ofsecond contact pads 212 located on the lower surface 104. Anencapsulating layer 244 encompasses the die, bond pads, and bond wires.Conductive leads 116 connect each of the first and second contact pads112, 212 to corresponding solder balls 118. The solder balls 118 arethen coupleable with terminals 122 on the printed circuit board 120 asdescribed above.

[0041] The stacked die package 200 advantageously provides the improvedthermal dissipation characteristics described above, as well as therecognized advantages of economical use of surface space on the printedboard afforded by the stacking of the die. For an electricallyconductive packaging substrate 102, an electrically insulative layer 117may be formed between the conductive leads 116 and the lower surface104, as shown in FIG. 7. For example, the conductive leads 116 may bemounted to the lower surface 104 on the electrically insulative layer117 (FIG. 5) such as, for example, an insulative tape material usingconventional tape automated bonding (TAB) techniques, to preventelectrical shorts. Alternately, some (or all) of the conductive leads116 may be disposed within via 115 formed within the packaging substrate102 (as shown in FIG. 5), or for an electrically insulative packagingsubstrate 102, the electrically insulative layer 117 may be eliminated.

[0042] Also, although the encapsulating layer 244 of the stacked diepackage 200 may be eliminated, the advantages of a hermetically sealeddie may be realized in a die package in accordance with the inventionthat also offers improved thermal dissipation characteristics over priorart die packages. Because the die are attached to the packagingsubstrate which has a relatively large surface area facing away from theprinted circuit board, improved thermal dissipation is achieved for diepackages having single or multiple die that are protected by anencapsulating layer 244.

[0043]FIG. 8 shows a method of packaging and testing 800 of the stackeddie package 200 of FIG. 7. In this embodiment, the method 800 begins bytesting 850 of the first and second die. The testing of the individualdie is preferably rigorous and comprehensive. In a determination step852 it is determined whether the first and second die testedsuccessfully. If not, the unsuccessful die is discarded 854, and themethod returns to the die testing step 850 until both die aresuccessfully tested.

[0044] After both die test successfully, the first and second die areattached together 855. The first die is then attached 856 to thepackaging substrate within the recess 106 to form the stacked diepackage 200. Alternately, the first die may be attached to the packagingsubstrate prior to the attachment of the first die to the second die.Next, the stacked die package is tested 858. Depending upon the tests852 conducted upon the first and second die prior to attachment 855 tothe packaging substrate, the testing of the stacked die package 858 maybe relatively simple.

[0045] In another determination step 860, it is determined whether thestacked die package has tested successfully. If the stacked die packagepasses the testing, an encapsulating layer may be applied 861, and themethod terminated successfully 863. Alternately, the encapsulating layermay be omitted.

[0046] If the package does not test successfully, however, adetermination is made whether the package has already been reworked 862.If the stacked die package has not previously been reworked, it isreworked 864 to correct the testing failures, such as, for example, byrewiring one or more of the first and second contact pads 110, 210 withthe first and second bond pads 112, 212 respectively. The reworked diepackage is then returned for testing 858.

[0047] If the die package does not test successfully 860 and it haspreviously been reworked 862, a determination is made whether thestacked die are salvageable 866. If so, the stacked die are salvaged 868and returned for attachment to a new packaging substrate 856, and thesubsequent acts are repeated. If the stacked die are not salvageable,however, the stacked die package is discarded 870, and the method 800 isterminated 872 with an unsuccessful result.

[0048] Although the method of packaging and testing 800 shown in FIG. 8involves a greater number of acts than are shown in the prior art method60 shown in FIG. 4, the method 800 is more economical. Individualtesting of the die prior to attachment to the packaging substratesimplifies the subsequent testing of the stacked die package, and makesdiagnosis of test failures easier. Also, the combination of individualdie testing 850 and testing of the stacked die package 858 prior toattachment to the printed circuit board improves the yield of thepackaging and testing process in comparison with the prior art method60. The method 800 reduces the effort involved in diagnosing testfailures, the effort involved in reworking die packaging, and the wasteand loss of production associated with discarding unsuccessfulcomponents.

[0049]FIG. 9 is a side cross-sectional view of a stacked die package 300in accordance with another embodiment of the invention. In thisembodiment, the stacked die package 300 is similar to the previouslydescribed stacked die package 200, except that the first die 108 iscoupled to the substrate 102 in a flip chip arrangement. Also, therecess 106 in this embodiment is more shallow so that the second die 208is not fully disposed within the recess 106.

[0050] As shown in FIG. 9, the first contact pads 112 are disposedwithin the recess 106 of the packaging substrate 102, and the first bondpads 110 on the first die 108 are in direct contact with the firstcontact pads 112 on the substrate 102. Conductive leads 116 connect thefirst contact pads 112 with a set of solder bumps 118. The second die208 is attached to the first die 108, and the second bond pads 210 arewire-bonded to the second contact pads 212 on the lower surface 104 ofthe substrate 102. Conductive leads 116 also connect the second contactpads 112 with corresponding solder bumps 118 which, in turn, are engagedwith the terminals 122 on the printed circuit board 120. As in thepreviously described embodiments, for an electrically conductivepackaging substrate 102, an electrically insulative layer 117 may beformed between the conductive leads 116 and the lower surface 104.Alternately, for an electrically insulative packaging substrate 102, theelectrically insulative layer 117 may be eliminated. The stacked diepackage 300 may be packaged and tested in accordance with the methodsdescribed above and shown on FIG. 8.

[0051] The stacked die package 300 advantageously provides the benefitsof the inventive packaging arrangement, including improved thermaldissipation, physical protection, and elimination of components asdescribed above, together with the benefits of flip chip packaging.Because the first lead wires 114 between the first bond pads 110 and thefirst contact pads 112 are eliminated, the electrical contact betweenthe first die and the packaging substrate is more reliable, and thespeed of the first chip is improved.

[0052] Although the stacked die package 300 is shown in FIG. 9 as havinga shallow recess 106, the depth of the recess 106 may be adjusted to anydesired depth in accordance with the requirements of the die package.For example, for some stacked die combinations, it may be desirable toincrease the depth of the recess to situate both the first and seconddie within the recess. Alternately, for other applications a shallowrecess may be preferred. Where a shallow recess is used, it may benecessary to increase the size of the solder bumps (or connecting pins)to increase the distance between the printed circuit board and thepackaging substrate to prevent the second die 208 or the second bondwires 214 from contacting the printed circuit board 120. Anencapsulating layer (see FIG. 7) may also be added to hermetically sealand protect the die, bond pads, contact pads, and bond wires.

[0053] The detailed descriptions of the above embodiments are notexhaustive descriptions of all embodiments contemplated by the inventorto be within the scope of the invention. Indeed, persons skilled in theart will recognize that certain elements of the above-describedembodiments may variously be combined or eliminated to create furtherembodiments, and such further embodiments fall within the scope andteachings of the invention. It will also be apparent to those ofordinary skill in the art that the above-described embodiments may becombined in whole or in part to create additional embodiments within thescope and teachings of the invention.

[0054] Thus, although specific embodiments of, and examples for, theinvention are described herein for illustrative purposes, variousequivalent modifications are possible within the scope of the invention,as those skilled in the relevant art will recognize. The teachingsprovided herein of the invention can be applied to other apparatus andmethods for packaging and testing of die, and not just to the apparatusand methods described above and shown in the figures. In general, in thefollowing claims, the terms used should not be construed to limit theinvention to the specific embodiments disclosed in the specification andthe claims, but should be construed to include all apparatus and methodsthat operate within the broad scope of the claims. Accordingly, theinvention is not limited by the foregoing disclosure, but instead itsscope is to be determined by the following claims.

1. A stacked die package coupleable with a circuit board, comprising: apackaging substrate including a first surface having a recess disposedtherein and a plurality of conductive leads coupled thereto, eachconductive lead having an inner end proximate the recess and an outerend coupleable with the circuit board; and a first die attached to thepackaging substrate within the recess and having a plurality of firstbond pads disposed thereon, each first bond pad being electricallycoupled to one of the inner ends; and a second die attached to the firstdie and having a plurality of second bond pads disposed thereon, eachsecond bond pad being electrically coupled to one of the inner ends, thefirst surface of the packaging substrate being proximate the circuitboard when the outer ends are coupled with the circuit board whereby thepackaging substrate at least partially encloses and protects both thefirst and second die.
 2. The stacked die package of claim 1 wherein theouter ends of the conductive leads comprise solder bumps engageable withterminals on the circuit board.
 3. The stacked die package of claim 1wherein the outer ends of the conductive leads comprise connecting pinsengageable with receptacles on the circuit board.
 4. The stacked diepackage of claim 1 wherein at least one of the first bond pads iselectrically coupled to one of the inner ends by a bond wire.
 5. Thestacked die package of claim 1 wherein at least some of the inner endscomprise first contact pads disposed within the recess, each of thefirst bond pads directly contacting one of the first contact pads. 6.The stacked die package of claim 1 wherein the packaging substratecomprises an electrically conductive substrate, further comprising anelectrically insulative layer formed between the conductive leads andthe packaging substrate.
 7. The stacked die package of claim 1 , furthercomprising an encapsulating layer disposed about the first and seconddie to protect the first and second die.
 8. The stacked die package ofclaim 1 wherein the second die is fully disposed within the recess. 9.The stacked die package of claim 1 wherein the first die is a flip chipmounted die and the second bond pads are wire-bonded to the inner endsof the conductive leads.
 10. The stacked die package of claim 1 whereinthe packaging substrate has a plurality of via formed therethrough, atleast some of the conductive leads being at least partially disposedwithin the plurality of via.
 11. The stacked die package of claim 10wherein the packaging substrate comprises an electrically conductivesubstrate, further comprising an electrically insulative layer formedbetween the conductive leads and the packaging substrate.
 12. Thestacked die package of claim 10 wherein each outer end comprises a ballpad coupleable with a conductive bump.
 13. The stacked die package ofclaim 12 , further comprising a conductive bump formed on each ball padand engageable with terminals on the circuit board.
 14. A stacked diepackage coupleable with a circuit board, comprising: a packagingsubstrate including a first surface having a recess disposed therein anda plurality of conductive leads formed thereon, each conductive leadhaving an inner end proximate the recess and an outer end coupleablewith the circuit board; a first die attached to the packaging substratewithin the recess and having a plurality of first bond pads disposedthereon, each first bond pad being electrically coupled to one of theinner ends; and a second die attached to the first die and having aplurality of second bond pads disposed thereon, each second bond padbeing electrically coupled to one of the inner ends, the first surfaceof the packaging substrate being proximate the circuit board when theouter ends are coupled with the circuit board.
 15. The die package ofclaim 14 wherein the outer ends of the conductive leads comprise solderbumps engageable with terminals on the circuit board.
 16. The diepackage of claim 14 wherein the outer ends of the conductive leadscomprise connecting pins engageable with receptacles on the circuitboard.
 17. The die package of claim 14 wherein at least one of the firstor second bond pads is electrically coupled to one of the inner ends bya bond wire.
 18. The die package of claim I wherein at least some of theinner ends comprise contact pads disposed within the recess, each of thefirst bond pads directly contacting one of the contact pads.
 19. A diepackage created by a method of packaging and testing, comprising:testing a die having a plurality of bond pads formed thereon;determining that the die has tested successfully; providing a packagingsubstrate including a first surface having a recess formed therein and aplurality of conductive leads coupled thereto; attaching the die to thepackaging substrate within the recess and with the bond padselectrically coupled to at least some of the conductive leads to formthe die package; and testing the die package.
 20. The die package ofclaim 19 wherein the method further comprises determining that the diepackage has tested successfully.
 21. The die package of claim 19 whereinthe method further comprises sealing the die in an encapsulating layer.22. The die package of claim 19 wherein attaching the die to thepackaging substrate within the recess and with the bond padselectrically coupled to at least some of the conductive leads comprisesaffixing the die to the packaging substrate within the recess with anadhesive and wire-bonding the bond pads to the at least some conductiveleads.
 23. The die package of claim 19 wherein attaching the die to thepackaging substrate within the recess and with the bond padselectrically coupled to at least some of the conductive leads comprisesmounting the bond pads of the die directly to the conductive leads. 24.A stacked die package created by a method of packaging and testing,comprising: testing a first die having a plurality of first bond padsformed thereon; determining that the first die has tested successfully;testing a second die having a plurality of second bond pads formedthereon; determining that the second die has tested successfully;attaching the second die to the first die; providing a packagingsubstrate including a first surface having a recess formed therein and aplurality of conductive leads coupled thereto; attaching the first dieto the packaging substrate within the recess and with the first andsecond bond pads electrically coupled to at least some of the conductiveleads to form the stacked die package; and testing the stacked diepackage.
 25. The stacked die package of claim 24 wherein the methodfurther comprises determining that the stacked die package has testedsuccessfully.
 26. The stacked die package of claim 24 wherein the methodfurther comprises sealing the first and second die in an encapsulatinglayer.
 27. The stacked die package of claim 24 wherein attaching thefirst die to the packaging substrate within the recess and with thefirst and second bond pads electrically coupled to at least some of theconductive leads comprises affixing the first die to the packagingsubstrate within the recess with an adhesive and wire-bonding the firstand second bond pads to the at least some conductive leads.
 28. Thestacked die package of claim 24 wherein attaching the first die to thepackaging substrate within the recess and with the first and second bondpads electrically coupled to at least some of the conductive leadscomprises mounting the first bond pads of the first die directly to theat least some conductive leads.
 29. A method of packaging and testing adie package, comprising: testing a die having a plurality of bond padsformed thereon; determining that the die has tested successfully;providing a packaging substrate including a first surface having arecess formed therein and a plurality of conductive leads coupledthereto; attaching the die to the packaging substrate within the recessand with the bond pads electrically coupled to at least some of theconductive leads to form the die package; and testing the die package.30. The method of claim 29 , further comprising determining that the diepackage has tested successfully.
 31. The method of claim 29 , furthercomprising determining that the die package has not previously beenreworked.
 32. The method of claim 29 , further comprising reworking thedie package.
 33. The method of claim 29 , further comprising determiningthat the die package is salvageable.
 34. The method of claim 29 ,further comprising salvaging the die package.
 35. The method of claim 29, further comprising sealing the die in an encapsulating layer.
 36. Themethod of claim 29 wherein attaching the die to the packaging substratewithin the recess and with the bond pads electrically coupled to atleast some of the conductive leads comprises affixing the die to thepackaging substrate within the recess with an adhesive and wire-bondingthe bond pads to the at least some conductive leads.
 37. The method ofclaim 29 wherein attaching the die to the packaging substrate within therecess and with the bond pads electrically coupled to at least some ofthe conductive leads comprises mounting the bond pads of the diedirectly to the conductive leads.
 38. A method of packaging and testinga stacked die package, comprising: testing a first die having aplurality of first bond pads formed thereon; determining that the firstdie has tested successfully; testing a second die having a plurality ofsecond bond pads formed thereon; determining that the second die hastested successfully; attaching the second die to the first die:providing a packaging substrate including a first surface having arecess formed therein and a plurality of conductive leads coupledthereto; attaching the first die to the packaging substrate within therecess and with the first and second bond pads electrically coupled toat least some of the conductive leads to form the stacked die package;and testing the stacked die package.
 39. The method of claim 38 ,further comprising determining that the die package has testedsuccessfully.
 40. The method of claim 38 , further comprising sealingthe die in an encapsulating layer.
 41. The method of claim 38 whereinattaching the die to the packaging substrate within the recess and withthe bond pads electrically coupled to at least some of the conductiveleads comprises affixing the die to the packaging substrate within therecess with an adhesive and wire-bonding the bond pads to the at leastsome conductive leads.
 42. The method of claim 38 wherein attaching thedie to the packaging substrate within the recess and with the bond padselectrically coupled to at least some of the conductive leads comprisesmounting the bond pads of the die directly to the conductive leads. 43.The method of claim 38 , further comprising determining that the stackeddie package has not previously been reworked.
 44. The method of claim 38, further comprising reworking the stacked die package.
 45. The methodof claim 38 , further comprising determining that the stacked diepackage is salvageable.
 46. The method of claim 38 , further comprisingsalvaging the stacked die package.